U.S. patent number 10,640,986 [Application Number 16/241,370] was granted by the patent office on 2020-05-05 for drywall joint tape and method.
This patent grant is currently assigned to UNITED STATES GYPSUM COMPANY. The grantee listed for this patent is UNITED STATES GYPSUM COMPANY. Invention is credited to Guy Rosenthal.
United States Patent |
10,640,986 |
Rosenthal |
May 5, 2020 |
Drywall joint tape and method
Abstract
A joint tape for drywall includes a substrate layer having an
elongate shape in a lengthwise direction and being flexible in the
lengthwise direction and in a transverse direction. The tape
further includes a covering layer disposed in bonding relation on
the substrate layer. The covering layer is rigid in the transverse
direction and configured to withstand compressive forces applied
generally in the transverse direction and shear stresses applied
generally along the transverse direction.
Inventors: |
Rosenthal; Guy (Wheaton,
IL) |
Applicant: |
Name |
City |
State |
Country |
Type |
UNITED STATES GYPSUM COMPANY |
Chicago |
IL |
US |
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Assignee: |
UNITED STATES GYPSUM COMPANY
(Chicago, IL)
|
Family
ID: |
52738731 |
Appl.
No.: |
16/241,370 |
Filed: |
January 7, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190136542 A1 |
May 9, 2019 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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14466736 |
Aug 22, 2014 |
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61885881 |
Oct 2, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E04F
21/1657 (20130101); B32B 37/14 (20130101); E04F
13/042 (20130101); Y10T 442/30 (20150401); Y10T
156/10 (20150115) |
Current International
Class: |
E04F
13/04 (20060101); E04F 21/165 (20060101); B32B
37/14 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2836312 |
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Dec 2012 |
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CA |
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2832989 |
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Nov 2006 |
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CN |
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201080690 |
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Jul 2008 |
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CN |
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0567109 |
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Oct 1993 |
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EP |
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2123259 |
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Nov 1974 |
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FR |
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2514806 |
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Apr 1983 |
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FR |
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580999 |
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Feb 1946 |
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GB |
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118660 |
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Jul 2012 |
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RU |
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9530810 |
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Nov 1995 |
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WO |
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2015050799 |
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Apr 2015 |
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WO |
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Other References
3 page PDF Machine translation of CN 201080690 Y which was cited on
the IDS filed Feb. 12, 2019. Published Jul. 2008. (Year: 2008).
cited by examiner .
Ukrainian Notice of Allowance from corresponding Ukrainian Patent
Application No. a201603992, dated Jun. 18, 2019. cited by
applicant.
|
Primary Examiner: Canfield; Robert
Attorney, Agent or Firm: Greer Burns & Crain Ltd.
Parent Case Text
PRIORITY CLAIM AND CROSS-REFERENCE TO RELATED APPLICATIONS
The instant application is a continuation of U.S. patent
application Ser. No. 14/466,736, filed on Aug. 22, 2014, which is
incorporated in its entirety by reference herein. The instant
application claims the benefit of the filing date of U.S.
Provisional Application No. 61/885,881, filed on Oct. 2, 2013, the
contents of which are hereby incorporated herein in their entirety
by this reference.
Claims
The invention claimed is:
1. A joint tape for drywall, comprising: a substrate layer having
an elongate shape to form a substrate strip, the substrate layer
extending in a lengthwise direction to define a length and
extending in a transverse direction that is perpendicular to the
lengthwise direction to define a width, the width being narrower
than the length, the substrate layer strip being made from
substrate fibers extending parallel to one another along the
lengthwise direction and having a substrate layer strip flexibility
in the lengthwise direction and the transverse direction; and a
covering layer having an elongate shape and disposed in overlapping
and bonding relation on the substrate layer, the covering layer
extending in the lengthwise direction and in the transverse
direction to form a strip that extends along the substrate layer
strip, the covering layer strip being made from covering fibers
extending parallel to one another along the transverse direction
and having a covering layer strip flexibility in the transverse
direction and configured to withstand compressive forces applied
generally in the transverse direction and shear stresses applied
generally along the transverse direction; wherein the substrate
fibers and the covering fibers contact each other at intersections,
and wherein the joint tape further includes bonds formed by
adhesive, the bonds being disposed at least at a majority of
intersections between the substrate fibers and the covering fibers
to bond the substrate fibers and the covering fibers to one
another, the adhesive being made from a material sufficiently rigid
so as to prevent the covering fibers from flexing at least locally;
wherein the covering layer strip flexibility is less than the
substrate layer strip flexibility.
2. The joint tape of claim 1, wherein the substrate layer is made
entirely of substrate fibers extending parallel to one another
along the lengthwise direction.
3. The joint tape of claim 1, wherein the covering layer is made
entirely of covering fibers extending parallel to one another along
the transverse direction.
4. The joint tape of claim 1, wherein the substrate fibers of the
substrate layer and the covering fibers of the covering layer are
made from different materials; wherein the substrate fibers are
made from reinforced plastic, glass, fabric or metal; and wherein
the covering fibers are made from metal, plastic, or glass.
5. The joint tape of claim 1, wherein the substrate fibers are made
of the same material as the covering fibers; wherein the covering
fibers have a greater diameter than the substrate fibers.
6. The joint tape of claim 1, wherein the adhesive comprises
settable epoxy.
7. The joint tape of claim 6, wherein the adhesive comprises an
adhesive mixture.
8. The joint tape of claim 1, wherein the bonds are disposed at
each of the intersections between the substrate fibers and the
covering fibers.
9. The joint tape of claim 1, wherein the bonds formed by the
adhesive increase an overall rigidity of the joint tape.
10. A drywall joint between two adjacent drywall panels,
comprising: a layer of joint compound disposed along generally
abutting edges of the two adjacent drywall panels; a joint tape
embedded within the layer of joint compound, the joint tape
comprising: a substrate layer having an elongate shape to form a
substrate strip, the substrate layer extending in a lengthwise
direction to define a length and extending in a transverse
direction that is perpendicular to the lengthwise direction to
define a width, the width being narrower than the length, the
substrate layer strip being made from substrate fibers extending
parallel to one another along the lengthwise direction and having a
substrate layer strip flexibility in the lengthwise direction and
the transverse direction; and a covering layer having an elongate
shape and disposed in overlapping and bonding relation on the
substrate layer, the covering layer extending in the lengthwise
direction and in the transverse direction to form a strip that
extends along the substrate layer strip, the covering layer strip
being made from covering fibers extending parallel to one another
along the transverse direction and having a covering layer strip
flexibility in the transverse direction and configured to withstand
compressive forces applied generally in the transverse direction
and shear stresses applied generally along the transverse
direction; wherein the substrate fibers and the covering fibers
contact each other at intersections, and wherein the joint tape
further includes bonds formed by adhesive, the bonds being disposed
at least at a majority of intersections between the substrate
fibers and the covering fibers to bond the substrate fibers and the
covering fibers to one another, the adhesive being made from a
material sufficiently rigid so as to prevent the covering fibers
from flexing at least locally; wherein the covering layer strip
flexibility is less than the substrate layer strip flexibility.
11. The drywall joint of claim 10, wherein the adhesive comprises
settable epoxy.
12. The drywall joint of claim 10, wherein the bonds are disposed
at each of the intersections between the substrate fibers and the
covering fibers.
13. The drywall joint of claim 1, wherein the bonds formed by the
adhesive increase an overall rigidity of the joint tape.
14. A method for manufacturing joint tape for use in drywall
joints, comprising: providing a substrate layer having a lengthwise
direction and a transverse direction that is perpendicular to the
lengthwise direction to form a substrate layer strip, the substrate
layer strip being made from substrate fibers extending parallel to
one another along the lengthwise direction and having a substrate
layer strip flexibility in the lengthwise direction and the
transverse direction; providing a covering layer having a
lengthwise direction and a transverse direction to form a covering
layer strip, the covering layer strip being made from covering
fibers extending parallel to one another along the transverse
direction and having a covering layer strip flexibility in the
transverse direction and configured to withstand compressive forces
applied generally in the transverse direction and shear stresses
applied generally along the transverse direction; depositing the
substrate and covering layers in overlapping relation to create a
joint tape preform, wherein the substrate fibers and the covering
fibers contact each other at intersections; and bonding the
substrate layer to the covering layer in the joint tape preform to
create a joint tape that is flexible in the lengthwise direction
but more rigid in the transverse direction than the lengthwise
direction, wherein bonding the substrate layer to the covering
layer includes forming bonds of adhesive at least at a majority of
the intersections between the substrate fibers and the covering
fibers to bond the substrate fibers and the covering fibers to one
another, the adhesive being made from a material sufficiently rigid
so as to prevent the covering fibers from flexing at least
locally.
15. The method of claim 14, wherein the bonds formed by the
adhesive increase an overall rigidity of the joint tape.
16. The method of claim 14, wherein the adhesive comprises settable
epoxy.
17. The method of claim 14, wherein the bonds are disposed at each
of the intersections between the substrate fibers and the covering
fibers.
18. The method of claim 14, wherein said forming bonds of adhesive
comprises passing the joint tape preform through a pool or vat of
adhesive, wherein the adhesive collects at the at least a majority
of intersections.
Description
BACKGROUND
Typical load bearing or separation wall assemblies in buildings are
made of support structures, for example, wooden or metal studs,
covered by wallboards. There are many different types of wallboard
for use depending on the requirements of various applications. One
wallboard type that is most commonly used to build internal walls
in buildings is gypsum wallboard, which is conventionally attached
to studs. Gypsum wallboards are available in various standard sizes
having predetermined width, for example, 4 ft., and predetermined
lengths such as 8 ft., 10 ft., or other sizes. In conventional
installations, wallboards are assembled end-to-end and/or
side-to-side to cover wall surfaces greater than the length or
width of the drywall sheets, which requires joints along edges of
wallboard sheets to be created.
Typical wallboard joints are constructed by a combination of a
joint compound and a matrix material to create a composite
structure lending strength to the joint. Similar processes are also
used to make wallboard repairs and/or finish inside and outside
wall corners. One matrix material commonly used for wallboard
joints is a rolled material, commonly referred to as "tape." When
constructing a joint, a layer of joint compound may be laid along a
joint before a layer of tape is added along and covering the joint.
One or more layer of joint compound may be added over the tape, and
over each other, as is known. The resulting layers of dried joint
compound and tape make up a composite joint structure that should
be able to withstand various stresses such as tensile, compressive
and shear stresses that may be present at the joint, such that
cracks and breaks are avoided as wall structures may shift, settle
or otherwise become stressed. However, this is not the case.
Although composite joint structures are generally effective in
withstanding tensile stresses, i.e., stresses tending to pull the
joint apart, they are not sufficiently resilient against
compressive or shear stresses tending to compress or slide the
joint.
There are two conventional types of tape used in the art today. The
first type, made of paper, includes a continuous or perforated tape
strip that offers little to no strength in the compressive
direction. The second type, made of fiberglass, is also weak in a
compressive stress direction. In general, fiberglass tape is not
ideal for stabilizing joints between drywall boards because, while
it has cross-directional fibers (short fibers whose length is the
width of the tape) that are strong in tension and provide excellent
resistance to tensile forces pulling the joint apart, it provides
almost no resistance to compressive forces that push the boards
closer together. Numerous drywall joint strength tests have shown
that fiberglass mesh tape makes a joint relatively strong when
tensile forces are placed on the joint, but when compressive or
shearing forces are placed on the joint, it fails easily. Joint
failure manifests itself as joint compound cracking, which requires
repair. For this reason, fiberglass joint tape is not recommended
for use with drying type joint compounds, which are not as strong
and crack-resistant as setting-type compounds.
Samples of a drywall joint made with Fibatape.RTM. tape have been
tensile tested in accordance with ASTM C 474 (Appendix) which
measures the strength to first crack of a tape-compound sample
coated in electrically conductive paint. The strength is measured
until the first crack in the paint occurs, which breaks the
electrical continuity along the surface and registers the ultimate
tensile load. Such failures suggest that typical taped joints do
not optimize the strength of the glass-joint compound composite. In
one mode of failure, tensile loads tend to separate the glass
fibers from the joint compound matrix instead of transferring these
loads to the glass fibers themselves.
SUMMARY
In one aspect, the disclosure describes joint tape for drywall
applications. The joint tape includes a substrate layer having an
elongate shape in a lengthwise direction and being flexible in the
lengthwise direction and in a transverse direction. The tape
further includes a covering layer disposed in bonding relation on
the substrate layer. The covering layer is rigid in the transverse
direction and configured to withstand compressive forces applied
generally in the transverse direction and shear stresses applied
generally along the transverse direction.
In another aspect, the disclosure describes a drywall joint between
two adjacent drywall panels. The joint includes a layer of joint
compound disposed along generally abutting edges of the two
adjacent drywall panels, and a joint tape embedded within the layer
of joint compound. The joint tape includes a substrate layer having
an elongate shape in a lengthwise direction along the generally
abutting edges. The substrate layer is flexible in the lengthwise
direction and in a transverse direction, which is perpendicular to
the lengthwise direction. The joint tape further includes a
covering layer disposed in bonding relation on the substrate layer.
The covering layer is rigid in the transverse direction and
configured to withstand compressive forces applied generally in the
transverse direction tending to push the two adjacent drywall
panels towards each other, and shear stresses applied generally
along the transverse direction tending to slide the two drywall
panels relative to one another along the abutting edges
thereof.
In yet another aspect, the disclosure describes a method for
manufacturing joint tape for use in drywall joints. The method
includes providing a substrate layer that is flexible in a
lengthwise direction and in a transverse direction. The method
further includes providing a covering layer that is flexible in the
lengthwise direction but is rigid in the transverse direction. When
manufacturing the joint tape, the substrate and covering layers are
deposited in overlapping relation to create a joint tape preform.
The substrate layer is then bonded to the covering layer in the
joint tape preform to create a joint tape that is flexible in the
lengthwise direction but rigid in the transverse direction.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a cross section of a wall board joint in
accordance with the disclosure.
FIG. 2 illustrates a roll of joint tape in accordance with the
disclosure.
FIGS. 3-6 illustrate various embodiments of joint tape in
accordance with the disclosure.
FIG. 7 illustrates a cross section of one embodiment for a joint
tape in accordance with the disclosure.
FIG. 8 illustrates an alternative embodiment for a joint tape in
accordance with the disclosure.
FIG. 9 illustrates a manufacturing method for a joint tape in
accordance with the disclosure.
DETAILED DESCRIPTION
The present disclosure is applicable to drywall or other wallboard
joints and, more particularly, to a joint tape for use in composite
joint structures including the tape embedded into one or more type
of joint compound. Various embodiments are described herein
relative to joint tape for drywall, but it should be appreciated
that the structures and methods relative to making or using joint
tape are applicable to other types of wall panels as well.
A cross section of a drywall joint 100 is shown in FIG. 1. The
drywall joint 100. as shown, is a composite joint formed between
two drywall panels 102. Each panel forms a recessed section 104
along a joint edge 106 to accommodate the materials making up the
joint 100 such that a flat surface is presented on an external
drywall surface 108. The joint 100 is referred to herein as a
"composite" joint, which means that the joint structure is made of
the combination of different materials. For example, the joint 100
in the illustrated embodiment includes overlapping layers of
hardened joint compound 110, a joint tape 112 embedded within the
hardened joint compound 110, and an optional skim-coat compound
layer 114, which is formable to a fine finish surface made to match
the external drywall surface 108. Advantageously, the hardened
joint compound 110 may be a drying type joint compound that, when
embedding the tape 112, forms a structure having superior
resistance to compressive and shear stresses that was previously
achieved. The tape 112, although shown embedded in the joint
compound, may alternatively include a layer of adhesive affixing it
directly onto the drywall before deposition of the joint compound.
As is known, joints between various wall panels may be assembled in
stages, which include material deposition, forming and sanding
between each application. In the illustrated embodiment, the joint
tape 112 is advantageously configured to withstand shear, tensile
and compressive stresses applied between the two wall panels
102.
A roll of joint tape 200 is shown in FIG. 2 to illustrate various
structural and/or functional aspects thereof. The roll 200 may be
made up of the same or a similar type of joint tape 112, as shown
and described in FIG. 1. The roll of joint tape 200 is
advantageously configured for dispensing appropriate lengths of
tape 202 during assembly of drywall joints. As can be seen in FIG.
2, the tape 202 is made of two layers--a substrate layer 204 and a
covering layer 208. As used herein, "layer" denotes a plurality or
group of fibers that share similar traits including but not limited
to a similar composition, size, function, and/or deposition
pattern, but not necessarily a particular positioning in the tape
structure. Therefore, while the two separate substrate and covering
layers are described and shown in accordance with a handful of
embodiments for joint tape, it is contemplated that the various
fibers that make up these layers can be woven together. In other
words, while the layers are shown and described separately in
certain embodiments, the substrate and covering layers may be woven
together in a single fabric.
In the illustrated embodiment, the substrate layer 204 forms the
substrate of the tape 202, has a generally elongate shape extending
along a major axis of the tape 202, and forms the material layer of
the tape 202 that permits the rolling of the tape 202 into the roll
200, provides flexibility for application and handling of the tape
202, and the like. In one embodiment, the substrate layer 204 may
include an adhesive permitting its installation directly onto the
drywall panels around a joint before the tape is embedded with
joint compound. The substrate layer 204 may be made of any
appropriate material having good flexing and strength properties
permitting the formation of the tape 202 in to the roll 200.
Materials considered appropriate for forming the substrate layer
204 include reinforced plastic, glass, fabric or metal, each of
which is formed into strings, threads or fibers 206 that are woven
or otherwise structured into an elongate shape. Depending on the
material used to make them, the fibers of the substrate layer 204
have sufficient flexibility to allow handling, application and
rolling of the tape because these fibers will extend in a
lengthwise direction relative to a seam between wall panels (along
edges 106, as shown in FIG. 1) and are, thus, not expected to
withstand considerable stresses after formation of the joint
100.
The covering layer 208 of the tape 202 forms the portion of the
joint structure 100 (FIG. 1) that provides superior resistance to
compressive and shear stresses than previously proposed tape
designs. In the illustrated embodiment, the covering layer 208 is
made from a plurality of transversely extending fibers 210, which
possesses rigidity along their respective axial direction such
that, the entire tape assembly can resist compressive and shear
stresses. For clarity, the lengthwise direction of the tape is
along the tape's rolling direction, which is illustrated with the
designation "L" in FIG. 2, and the transverse direction is the
direction perpendicular to the lengthwise direction, which is
illustrated with the designation "W" in FIG. 2.
In the tape 202, the cross-fibers 210 in the covering layer 208 are
made of metal, glass, plastic or another suitable material that can
be formed into fibers and that possesses resistance to buckling
under compressive or shear stresses when integrated into a matrix
of settable cementitious material such as set drywall joining
compound. In one contemplated embodiment, the fibers making up the
substrate layer 204 have different mechanical properties than the
fibers making up the covering layer 208 so that each layer can be
tailored or configured to account for flexibility (substrate layer)
and rigidity (covering layer). In one embodiment, the fibers in the
covering and substrate layers 204 and 208 are woven together such
that the tape is made up of a single fabric layer. In other words,
the tape 202 is advantageously flexible in the lengthwise
direction, which allows the tape to be handled, installed and
packaged, and rigid in the cross-wise or transverse direction,
which enables to the joint 100 to withstand compressive and shear
loading.
The desired difference in mechanical properties between the
substrate and covering layers 204 and 208 can be accomplished by
different methods. In one embodiment, the fibers between the two
different layers may be made of different materials, for example,
flexible fabric or glass mat for the substrate layer 204 and rigid
plastic for the covering layer 208. Alternatively, the fibers may
be made of the same material, for example, glass, plastic or metal,
but have different gauges or cross-sectional sizes, with thinner,
more flexible fibers making up the substrate layer and thicker,
more rigid fibers, making up the covering layer. Moreover, the
pattern of fiber arrangement in either layer can also help increase
resistance to shear and compressive stresses.
Four different embodiments for the arrangement of fibers at least
in the covering layer for the tape 202 are shown in FIGS. 3-6. In
these embodiments, the bottom end of the tape is shown partially
unraveled for illustration, and the substrate layer 204 is shown
made up of the fibers 206 extending parallel to one another for
simplicity. It should be appreciated that in the tape embodiments
shown in FIGS. 3-6, the fibers of the various substrate and
covering layers are woven together into a single fabric, which is
shown from a top view for simplicity. In a first tape embodiment
302, shown in FIG. 3, the covering layer 208 is made of fibers 304
that extend parallel to one another in the transverse direction W.
The covering layer fibers 304 are disposed at a spacing, d, from
one another, which is selected based on the fiber width and the
fiber material empirically to provide optimum compressive
performance when embedded in a set cementitious joint compound
material.
In a second tape embodiment 306, shown in FIG. 4, the covering
layer 208 is made of fibers 308 that extend at an angle, .alpha.,
with respect to the transverse direction W. In the illustrated
embodiment, the angle .alpha. is about 60.degree., but other angles
may be used. The based on the fiber width and the fiber material
empirically to provide optimum compressive performance when
embedded in a set cementitious joint compound material.
In a third tape embodiment 310, shown in FIG. 5, the covering layer
208 is made of two different layers of fibers 312 arranged in a
crisscross configuration as shown. Specifically, a first network of
fibers 312 includes fibers that extend parallel to one another at a
first angle, .alpha.1, and a second network of fibers 312 includes
fibers that extend parallel to one another at a second angle,
.alpha.2. To maintain symmetry and to permit installation of the
tape in either direction, in the illustrated embodiment,
.alpha.1=180.degree.-.alpha.2. As shown, .alpha.1 is equal to about
60.degree., and .alpha.2 is equal to about 120.degree.. In each of
the first and second networks of fibers, the fibers 312 are
disposed at a spacing, d, from one another, which is selected based
on the fiber width and the fiber material empirically to provide
optimum compressive performance when embedded in a set cementitious
joint compound material. As compared to the tape 306, the tape 310
may be better equipped to handle shear and compressive stresses
owing to the increased covering layer fiber density, and to the
angled disposition of the covering layer fibers in two directions,
which can withstand non-transversely applied compressive
stresses.
In a fourth tape embodiment 314, shown in FIG. 6, the covering
layer 208 is made of three different layers of fibers 312 arranged
in a crisscross and in a transverse configuration as shown.
Specifically, a first network of fibers 316 includes fibers that
extend parallel to one another at a first angle, .alpha.1, a second
network of fibers 316 includes fibers that extend parallel to one
another at a second angle, .alpha.2, and a third network of fibers
316 includes fibers that extend parallel to the transverse
direction W. To maintain symmetry and to permit installation of the
tape in either direction, in the illustrated embodiment,
.alpha.1=180.degree.-.alpha.2. As shown, .alpha.1 is equal to about
60.degree., .alpha.2 is equal to about 120.degree., and the third
network of fibers is parallel to the transverse direction W, or, at
an angle of 0.degree.. In each of the first, second and third
networks of fibers, the fibers 316 are disposed at a spacing, d,
from one another, which is selected based on the fiber width and
the fiber material empirically to provide optimum compressive
performance when embedded in a set cementitious joint compound
material. As compared to the tape 310, the tape 314 may be better
equipped to handle shear and compressive stresses owing to the
increased covering layer fiber density, to the angled disposition
of the covering layer fibers in two directions, and to the
additional fiber layer, which can together withstand transversely
and non-transversely applied compressive stresses.
To augment the rigidity of the tape 202, in certain embodiments, an
adhesive structure or operation may be added to bond the substrate
and covering layers to one another so that a more rigid tape
structure can be created. Two possible embodiments are shown in the
cross sections of FIGS. 7 and 8. In these figures, where like
reference numerals are used to denote similar structures as
previously described for simplicity, cross sections are taken from
one exemplary tape embodiment, here, the tape 202 shown in FIG. 2.
In each section, the substrate layer fibers 206 are shown at the
bottom of the illustration, and the covering layer fibers 210 are
shown, in cross section, at the top of the illustration.
In the first illustration, an adhesive 402 is added at every or, at
least, at a majority of intersections between substrate and
covering fibers. The adhesive 402 bonds the two fibers to each
other and is made from a very rigid material, for example, settable
epoxy, that prevents the covering layer fibers from flexing at
least locally, thus increasing the overall rigidity of the tape
202. In the second illustration, as shown in FIG. 8, the adhesive
402 is omitted in favor of a welding operation performed to fuse
the substrate fibers to the covering layer fibers at the points of
intersection 404 between the two fiber arrangements. Such fusing or
welding may be accomplished by different methods and on different
materials. For example, in embodiments where both the substrate and
the covering layer fibers are made of plastic, the fusing operation
between the fibers at each intersection 404 may be accomplished by
heating the tape to locally melt the fiber material so it can fuse,
by ultrasonic welding operation, by exposure of the materials to a
solvent, and by other appropriate methods.
A block diagram schematically illustrating a joint tape
manufacturing process 406 in accordance with the disclosure is
shown in FIG. 9. In the illustrated embodiment, a first feed roll
408 containing a substrate layer preform 410 supplies the preform
via auxiliary rollers 412 to a layering station 414.
Simultaneously, a second feed roll 416 containing a covering layer
preform 418 supplies the respective preform to the layering station
414, where the two preforms meet to make up a joint tape preform
420. The joint tape preform 420 passes through a bonding station
422, where the preforms are pressed together and, optionally,
bonded, to create a tape 202 that is rolled into a joint tape roll
422. Additional optional operations such that the application of
wall adhesive and release paper on the back of the tape may also be
carried out but are not shown here for simplicity.
When assembling the tape 202, various considerations can be taken
into account. For example, the joint tape preform 420 may be formed
as a mat having a width equivalent to multiple joint tape widths,
which is then cut into sections making up each desired joint tape
roll package. Moreover, in one alternative embodiment, each of the
substrate layer and covering layer preforms may be manufactured on
demand, for example, by plastic extrusion of fibers, instead of
being preformed into fibers that are then used to assemble the
tape. The bonding station 422 may apply pressure and/or adhesive to
bond the substrate and covering tape layers to one another in one
step or in multiple steps. Alternatively, the bonding station may
include a pool or vat of adhesive through which the tape passes so
that adhesive collects at the fiber intersection sites and
otherwise drains off the remaining tape structure. In embodiments
where more than one fiber layer makes up the covering tape layer,
as between the covering fiber layers, the fibers may be connected
to each other using adhesive or may alternatively be tangled or
woven to each other by mechanical means.
It will be appreciated that the foregoing description provides
examples of the disclosed system and technique. However, it is
contemplated that other implementations of the disclosure may
differ in detail from the foregoing examples. All references to the
disclosure or examples thereof are intended to reference the
particular example being discussed at that point and are not
intended to imply any limitation as to the scope of the disclosure
more generally. All language of distinction and disparagement with
respect to certain features is intended to indicate a lack of
preference for those features, but not to exclude such from the
scope of the disclosure entirely unless otherwise indicated.
Recitation of ranges of values herein are merely intended to serve
as a shorthand method of referring individually to each separate
value falling within the range, unless otherwise indicated herein,
and each separate value is incorporated into the specification as
if it were individually recited herein. All methods described
herein can be performed in any suitable order unless otherwise
indicated herein or otherwise clearly contradicted by context.
The following examples further illustrate the invention but, of
course, should not be construed as in any way limiting its
scope.
Example 1
This Example illustrates the shear strength of conventional
fiberglass tape containing additional rigid members, for example,
metal reinforcements, which are found to enhanced rigidity in the
transverse direction of a joint. Wallboard samples 1A and 1B were
prepared by cutting 3'' by 8'' drywall panels and constructing a
joint by aligning the long dimensions of the panels in an offset
manner, overlapping by four inches.
A 50/50 mixture by mass of Hardman.RTM. Part A 8173 and
Hardman.RTM. Part B 8173 adhesives was applied in a thin layer
along the paper surface of the two panels' adjoining sides. Metal
reinforcements were then equally spaced perpendicular to the joint
and connected the two panels. The metal reinforcements were lightly
pressed into the layer of adhesive and allowed to adhere to the
board surface for 24 hours. A section of SHEETROCK.RTM. Fiberglass
Drywall Tape was adhered directly to the metal reinforcements and
board along the joint. A thin layer of joint compound
(SHEETROCK.RTM. All-Purpose Joint Compound, Ready-Mixed) was
applied over the adhered fiberglass mesh tape using 22-gauge guide
bars placed three inches apart. The 22-gauge coat was allowed to
dry for 24 hours, and the joint was filled using 16-guage guide
bars to produce a 4'' by 3'' by 0.055'' layer of joint
compound.
All measurements were made on an ATS Model contained in a
controlled temperature/humidity room held at 70.degree. F./50% R.H.
The prepared sample was then mounted in the test fixture and the
test was performed in compression mode. Results for the shear
strengths are provided below in Table 1, where "Fiberglass" tape
denotes SHEETROCK.RTM. Fiberglass Drywall Tape that was installed
using SHEETROCK.RTM. All-Purpose Joint Compound (Ready-Mixed) onto
the samples, and "Paper" tape denotes SHEETROCK.RTM. Paper Tape
that was installed using SHEETROCK.RTM. All-Purpose Joint Compound
(Ready-Mixed).
TABLE-US-00001 TABLE 1 Tape Shear Strength (lbs) Fiberglass* 60
Sample 1A 123.7 Sample 1B 117.3 Paper** 122
The use of the terms "a" and "an" and "the" and "at least one" and
similar referents in the context of describing the invention
(especially in the context of the following claims) are to be
construed to cover both the singular and the plural, unless
otherwise indicated herein or clearly contradicted by context. The
use of the term "at least one" followed by a list of one or more
items (for example, "at least one of A and B") is to be construed
to mean one item selected from the listed items (A or B) or any
combination of two or more of the listed items (A and B), unless
otherwise indicated herein or clearly contradicted by context.
Accordingly, this disclosure includes all modifications and
equivalents of the subject matter recited in the claims appended
hereto as permitted by applicable law. Moreover, any combination of
the above-described elements in all possible variations thereof is
encompassed by the disclosure unless otherwise indicated herein or
otherwise clearly contradicted by context.
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